The present invention pertains to the inspection of the end faces of optical fibers. Contamination of fiber optic end faces is the cause of a significant number of fiber optic system failures. A single contaminant particle on the end face of an optical fiber can cause significant back reflection, insertion loss, and equipment damage. Visual fiber optic end face inspection is the only way to determine if the end faces of optical fibers are clean, and is essential to reliable functionality.
There are many products in the art of visual fiber optic end face inspection. Most of these products are video inspection probes that include an inspection probe connected to a handheld viewing device via a cable. The inspection probe captures video of the fiber optic connector end face, which is transmitted to the handheld viewing device through the cable and displayed on a screen for viewing the video transmitted by the inspection probe. The operator applies the inspection probe to the fiber optic end face and, while viewing the screen, manually focuses the video on the fiber optic end face. The operator may then assess the video image to determine the condition of the fiber optic end face. In one variation within the art, some inspection probes use video to locate the fiber optic end face. The operator then manually focuses the video on the fiber optic end face and then captures a still image of the fiber optic end face once it is located and manually focused upon. From there, the operator may assess the still image from the handheld viewing device, as described above. In addition, there are software products on the market that may be used in conjunction with the handheld viewing device that may make the assessment automatically. All prior art fiber optic end face inspection products, as discussed above, require manual focusing, even in the last example where the assessment is automatic but not the focusing.
Although capable of performing the necessary task, conventional video inspection probes have significant disadvantages. The ergonomics of using the video inspection probe, for example, are neither efficient nor safe. The available products all depend on operator skill and precision in focusing on the fiber optic end face. This requires the use of at least one of the operator's hands for focusing, as well as the time necessary to focus. Moreover, all of these products include the inspection probe tethered in some manner to the handheld viewing device. Thus, the operator needs to bring the handheld viewing device with him for any inspections, in addition to the inspection probe. When the connector housing the fiber optic end face to be inspected is positioned such that its inspection requires use of a ladder, or is otherwise difficult to reach, the user may be put into an awkward and/or unsafe position. This is illustrated with reference to FIGS. 6A and 6B, which show a user on a ladder using a conventional video inspection probe. For personal safety reasons, the user will usually need to use one hand to secure his position. He also must use one hand to hold the inspection probe. He also needs to hold the handheld viewing device. He may be able to hold it in the same hand that is securing his position, but this could jeopardize his grip, and, therefore, his safety. Even if he is able to affix the handheld viewing device to his person, relieving the need to hold it in his hand, the viewing device is still tethered to the inspection probe. Should the tether be too short, he may have to position himself awkwardly and unsafely to reduce the distance between the two devices. Alternatively, he may have to stretch the tether, risking damage to the devices and the possibility that the surprise of a break would unseat him. Should the tether be too long, he risks entangling himself, the devices, and other objects around him, again posing a risk to his safety. In summary, the need to juggle both the handheld viewing device and the inspection probe, tethered together, and to ensure his own safety, present a risk to the user's safety as well as a risk of damage to the inspection probe, the handheld viewing device, or both, which would require costly repairs or replacement.
These systems also require that the data be analyzed on the small screen of the handheld viewing device; a device which may have limited functionality beyond basic viewing and analysis capabilities. In addition, the total portable video inspection probe system, including the inspection probe with video capabilities and the handheld viewing device with viewing screen, requires significant battery power that needs frequent recharging. Finally, when the user plugs the probe into the connector or adaptor within which the fiber optic end face to be tested is disposed, he needs to keep the probe aligned with the fiber optic end face within each connector or adaptor and rotate a focusing wheel at the same time. As a result, the user continuously shakes the probe, which makes the focusing task difficult to perform and greatly increases the time that it takes to check the fiber optic end face within each connector.
One possible solution to the problems inherent in conventional video inspection probes would be to wirelessly transmit the image data from the inspection probe to the viewing device. However, this option has not been implemented for a number of reasons. First, video streaming via wireless transmission is limited by the speed at which the screen may be refreshed. Thus, images are often blurry and the operator may have difficulty determining exactly when the video probe has been correctly placed and is focused. Moreover, the power necessary to continuously transmit video wirelessly would be significant, requiring a bulky battery and/or frequent battery charging.
Therefore, there is a need for a fiber optic end face inspection probe that does not have these disadvantages. Specifically, there is a need for an inspection probe that does not require manual focusing; that is not tethered to another piece of equipment; that will not use significant power; that may be used in conjunction with viewing devices other than handheld viewing devices; and that may quickly transmit images of the fiber optic end faces to different devices.